On the tile thread it has been asked about wallpaper glue. The contractor came today about something else, so I asked her what she used. She said they make it themselves. Now, I knew about this, but thought that it was no longer necessary given the modern adhesives available. As far as I could determine they are using cornstarch, but as I received the expected blank look when I asked about pre-glued wallpaper, caveat emptor.

The attached photos also show some local product, plus another that is made in China, but I cannot find that one on sale here.